| 摘要 |
PROBLEM TO BE SOLVED: To obtain a bushing the outer peripheral surface of which is finishing-formed into a prescribed diameter with high accuracy and which is excellent in the coaxial accuracy of the outer peripheral surface with the inner peripheral surface, also, the coaxial accuracy of the center axis of the inner peripheral surface with the center axis of the taper surface. SOLUTION: A cylindrical blank D is forced into the inner peripheral part 1a of a die 1 with a punch 2 on one side and also, by forcing the small-diameter tip parts 2a, 3a of a pair of punches 2, 3 into both end parts of the inner peripheral part D2 of the cylindrical blank D while restraining both end parts of the forced cylindrical blank D with cylindrical members 4, 5 which are provided on the outside of the punches 2, 3 movably relatively to the punches 2, 3, the outer peripheral surface D1 of the cylindrical blank D is finishing-formed into a prescribed diameter by the inner peripheral surface 1a of the die 1 and also the taper surfaces E3, E4 are simultaneously formed in both end parts of the inner peripheral surface D2 of the cylindrical blank D. COPYRIGHT: (C)2004,JPO |
